Research news

Streptomyces coelicolor is a soil-dwelling, filamentous bacterium responsible for producing most of the natural
antibiotics used in human and veterinary medicine. In the May 9 Nature, Stephen Bentley and colleagues from The Wellcome Trust Sanger Institute, Cambridge, UK and the John Innes Centre, Norwich, UK, report the complete genome sequence of the model actinomycete S. coelicolor A3(2).

Bentley et al. used an ordered cosmid library to sequence the S. coelicolor genome. They observed that at 8,667,507 base pairs the linear chromosome of this
organism has the largest number of genes so far discovered in a bacterium - 7,825
- many located in 20 gene clusters coding for known or predicted secondary metabolites.

"The genome contains an unprecedented proportion of regulatory genes, predominantly
those likely to be involved in responses to external stimuli and stresses, and many
duplicated gene sets that may represent 'tissue-specific' isoforms operating in different
phases of colonial development, a unique situation for a bacterium," wrote the authors.

In addition, there is an ancient synteny between the central 'core' of the chromosome
and the whole chromosome of Mycobacterium tuberculosis and Corynebacterium diphtheriae - two other pathogenic actinomycetes.

"The genome sequence will greatly increase our understanding of microbial life in
the soil as well as aiding the generation of new drug candidates by genetic engineering"
conclude the authors.